public class Demofs9 {
    int getKLevelNodeCount(BinaryTree.TreeNode root, int k) {
        if(root==null){
            return 0;
        }
        if(k==1){
            return 1;
        }
        return getKLevelNodeCount(root.left,k-1) + getKLevelNodeCount(root.right,k-1);
    }
}
